border-1px($color)
  position: relative
  &:after
  	display: block
  	position: absolute
  	left: 0
  	bottom: 0
  	width: 100%
  	border-top: 1px solid $color
  	content: ' '
  	
bg-image($url)
   	background-image: url($url + "@2x.png")
 		@media (-webkit-min-device-pixel-ratio: 3), (-min-device-pixel-ratio: 3)
 			background-image: url($url + "@3x.png")
 	  